Automated preparation of corrugated boxes, or like transporting containers has become commonplace to meet the tremendous demands of bulk transportation of consumer products. There is an increasing need today for even swifter and more efficient formation of boxes for storing and shipping those products in order to keep the production costs as low as possible. Box-forming machines have been successfully utilized to maintain the pace in the past, but continued improvement in operation efficiency is desirable.
The standard box-forming machine, generally known in the art as a flexo-folder-gluer machine, operates on the fibreboard blank by scoring to increase flexibility and thus allow efficient folding, applying glue to the appropriate flaps/tabs for a secure adhesive bond and folding the blank to establish the final box configuration. As part of the forming process, relief areas are also cut from the blank so that when folded, the box presents a body with straight edges and allows the glued areas to be properly aligned for sealing.
While the rotary cutters of the present box-forming machine are ideally designed to completely sever the cut-out portion or waste tab that defines the relief area, from time to time the waste tab is not completely removed. It can be appreciated that an unremoved tab can disrupt the downstream operation of the box-forming machine. The waste tab may cause jamming during the downstream folding or gluing processes. Also, even if jamming is avoided, the waste tab may prevent the box from being properly folded, resulting in a deformed or unsealed, and thus unusable, box. There is thus presented a need to insure the complete removal of the waste tabs prior to further processing in order to maximize efficiency in the box-forming process.
An early approach used to form relief areas in blanks involves the use of cut-and-punch devices designed to cut and positively punch the cut tab off the blank. Such devices have met with only limited success. The box-forming machines using this intermittent method of forming necessarily are slower than machines using rotary cutters that operate on a continuous, non-stepped flow of blanks.
One approach that has been used with the rotary cutting machines in recent years to assure removal of the waste tab involves the use of a fixed brush positioned in the path of the blank downstream from the cutting station of the box-forming machine. As the blank travels across the stationary bristles of the brush, the sweeping action is supposed to strip any waste tab that remains hanging from the blank. While this design is generally effective, it occasionally fails to cleanly remove the tab causing a jam or improperly formed box. Also, the engagement between the bristles and the blank tends to retard the forward motion of the blank, causing the box blank to skew and further disrupting the forming process.
A somewhat similar idea for tab removal is presented in Canadian Patent 792,063 to Kirby et al, issued Aug. 13, 1968. A rotating brush is positioned transversely across the path of the blank downstream from the cutting station and rotates in a direction counter to the forward motion of the blank. Such a design provides a positive, more efficient sweeping action for removing a waste tab that might remain hanging by a fiber strand.
Thus, the transversely oriented, rotating brush has proven effective in removing some unsevered waste tabs, but still imparts a disadvantageous retarding and skewing action. It is also not always effective when the unsevered waste tab remains attached so as to lay in the plane of the blank. In addition, it does not efficiently remove tabs cut to define a relief area on the trailing edge of the blank. More specifically, an unsevered waste tab remains attached to the blank generally at the inside corner of the relief area. Therefore, as the blank travels in a forward direction with an unsevered waste tab on the trailing edge of the blank, a sweeping force applied against the direction of travel tends to fold the tab back up to the plane of the blank. Thus, it can be appreciated that the counterrotating action of the transverse brush simply folds the waste tab flat against the blank and is generally unreliable in the removal of tabs from the trailing edge.
Accordingly, there remains a need to efficiently strip or remove unsevered waste tabs from both the leading edge and trailing edge of a blank in a box-forming machine. The stripping apparatus would not substantially interfere with the forward motion of the blank as it travels downstream while insuring the removal of all remaining waste tabs to provide efficient downstream processing. The stripping apparatus would advantageously apply a stripping force laterally across the path of the blank to pull the tab sideways rather than folding the tab up into the plane of the blank. Such a waste tab stripping apparatus would be economical to manufacture and be easily retrofitted and integrated with the other components of the box-forming machine.